This invention relates to new and useful improvements in spray marking devices particularly adapted for use in conjunction with agricultural or horticultural spraying equipment, for the purpose of visually showing where the implement has traversed.
This is required in order to avoid firstly, an overlap of the spraying fluids and secondly, a missed area of spraying fluids.
There has been an increasing demand for effective yet inexpensive marking devices for indicating visually, the width traversed by agricultural or horticultural spraying and spreading implements which may apply liquid and granular herbicides, insecticides and fertilizers.
It has become extremely important for the operator to be able to determine accurately the area covered by the previous pass of the machine so as not to overlap in an application or to miss areas. With today's spray concentrates, overlaps may cause some crop damage and misses lead to considerable financial waste inasmuch as weeds, insects and the like are not controlled.
The mechanical methods used in the past have caused considerable crop damage and have often been limited in application. Some of the present devices have not proven to be terribly effective as the marks have not been as visible as required under certain conditions or they have not had the lasting effects required in many cases. Some devices and marking methods have experienced many mechanical problems and have proven to be quite expensive and there has also been a great need for a device which is adaptable to all spraying and spreading implements.
One of the principal disadvantages of current implements is the fact that the pump and control valve are normally situated adjacent the center of the implement with the lines leading to a discharge nozzle at the end of the boom which may be some 30 to 40 feet away from the control valve. This means that the pressure has to be built up in the relatively long lines before discharge can occur so that the marking liquid is often dispersed or scattered through drift.
Another disadvantage is that when not in use, pressure and/or marking liquid often leaks away in the lines between the valve and the discharge nozzle.